When completing a well, production zones are provided by submerging a casing string having annular barriers into a borehole or a casing of the well. When the casing string is in the right position in the borehole or in another casing in the borehole, the annular barriers are expanded, swelled or inflated to isolate a first zone and a second zone between a well tubular structure and the borehole or an inner and an outer tubular structure. In some completions, the annular barriers are expanded by pressurised fluid, which requires a certain amount of additional energy. In other completions, a compound inside the annular barrier is heated so that the compound becomes gaseous, hence increasing its volume and thus expanding the expandable metal sleeve.
However, since it may be difficult to control if the expansion of the annular barrier has been performed correctly, uncertainty may arise regarding the isolation and sealing properties of the annular barrier between the first and second zones if the well does not function as planned after completion.
Two annular barriers are thus used to isolate a production zone, and testing the pressure and temperature through the production opening in the production casing in between the two annular barriers may be easily performed by means of a testing tool, known from US 2003/213591. However, testing of isolation and sealing properties of the annular barriers cannot be tested by such tools.